Rockbiter Weapon (RW) is very cost efficient because it adds 3 damage for 1 cost. Unfortunately, it is not as mana efficient as the Paladin's Blessing of Might because the effect is not permanent. However, this spell has the added utility of being able to cast it on your Hero.

Use this ability on your Hero if you want to be able to attack more units in one turn or you want to save the health of one of your minions.

Usually, it is not a good idea to use this ability on turn 1 to damage the enemy Hero.

One of the best uses of Rockbiter Weapon is to cast it on a minion with Windfury so that it can use the buff twice for an extra 6 damage. If Rockbiter Weapon is used on an Raging Worgen (RW), the RW can do 14 damage in one turn.